the coagulation of the casein in the stomach, in which case a certain
amount of limewater is used. Its action is to swell the protein of the
milk and in this way effect the precipitation of the casein. In other
cases it is found advisable to prevent the formation of curd and
hasten its departure from the stomach. Cannon[69] claims that milk
before it coagulates leaves the stomach quickly like water in gushes.
Hence, if an alkali like limewater, bicarbonate or citrate of soda is
added to the milk this coagulation will be checked and the digestion
be facilitated.

~Amount and Type of Alkali Used.~--The amount of alkali[70] necessary
to bring about any change in the general effect of the formula must be
determined by the amount of milk and cream in the mixture, since these
constituents alone determine the acid content. However, it is
impossible to judge exactly the amount of alkali to add, but an
approximate estimate is made from the work done by the various
investigators. It has been estimated that from 25 to 50% of limewater
must be added to milk to change it to any marked degree. In using
bicarbonate of soda, a much less quantity brings about the desired
result, 1-1/2 grains of bicarbonate of soda being equal to one ounce
of limewater. The action of these two alkalies is different. The soda
acting upon the milk causes the curds to be more porous, and therefore
more easily acted upon in digestion.

Sodium citrate likewise tends to prevent the formation of tough
curds. It is added in amounts of 1 to 2 grains to each ounce of milk
or cream in the mixture whenever it is found necessary to use it at
all.

The addition of any alkali to the formula is resorted to if the
symptoms indicate the need for it, but the type and quantity is
entirely within the province of the physician, not the nurse.

~The Addition of Sugar.~--~Lactose~ is the form in which the
carbohydrates are found in milk, and it has been a general rule to
employ this sugar in making up the sugar content of a formula, using
from 6 to 7% of the mixture in this form to cover the necessary energy
requirements of the infant. Other sugars are used, however; and of
late years malt sugar has been widely employed for this purpose. The
form now generally accepted is known as ~dextri-maltose~, which is a
combination of dextrin and maltose, both of which are readily acted
upon by the sugar-splitting enzymes of the digestive juices. In
digestion, lactose or milk sugar